Patent Document 1 conventionally discloses a vehicle air conditioner including an evaporator of a refrigeration cycle, serving as a heat exchanger for cooling air to be blown into an interior of a vehicle. The vehicle air conditioner is adapted to suppress the generation of bad odor from the air at the evaporator.
The reason for generation of such bad odor is that material causing the bad odor is attached to an outer surface of the evaporator when the air is cooled down to the dew-point temperature or less and condensed by the evaporator. The bad odor of the air is known to become stronger especially when the outer surface of the evaporator with the material causing the bad odor is dried or gets wet.
The vehicle air conditioner disclosed in Patent Document 1 controls a refrigerant discharge capacity of a compressor of the refrigeration cycle such that a refrigerant evaporation temperature at the evaporator is higher or lower only by a predetermined temperature than the dew-point temperature of the air flowing into the evaporator. Thus, the outer surface of the evaporator can be prevented from being repeatedly dried and getting wet to thereby suppress the generation of the bad odor from the air.